The present invention relates to a method or apparatus for producing direct reduced iron and a method or apparatus for producing a reducing gas therefor.
As a method for producing metal iron by reducing iron ore, the direct reduction process and the blast furnace iron-making process are known. In the direct reduction process, metal iron typically is produced by reducing iron ore in solid phase using a reducing gas containing hydrogen and carbon monoxide which is obtained by reforming a natural gas (refer to Japanese Examined Patent Publication No. 7-5951, and Yutaka Inada, “Improvements in the MIDREX® Direct Reduction Process,” R&D Kobe Steel Engineering Reports, Oct. 2000, Vol. 50, No. 3, pp. 86-89).
Methane, which is the main component of natural gas, is converted into hydrogen and carbon monoxide by steam reforming using an external-heating type reformer. Waste heat generated in the external-heating type reformer is reutilized in the reformer, e.g., for preheating the natural gas, for generating steam, and for preheating burning air.